EP0079959B1 - Tete d'enregistrement magnetographique - Google Patents

Tete d'enregistrement magnetographique Download PDF

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Publication number
EP0079959B1
EP0079959B1 EP82902146A EP82902146A EP0079959B1 EP 0079959 B1 EP0079959 B1 EP 0079959B1 EP 82902146 A EP82902146 A EP 82902146A EP 82902146 A EP82902146 A EP 82902146A EP 0079959 B1 EP0079959 B1 EP 0079959B1
Authority
EP
European Patent Office
Prior art keywords
recording
magnetic
medium
conductor
zone
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP82902146A
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German (de)
English (en)
Other versions
EP0079959A1 (fr
EP0079959A4 (fr
Inventor
George Gideon Pick
Houshang Rasekhi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Wang Laboratories Inc
Original Assignee
Wang Laboratories Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Wang Laboratories Inc filed Critical Wang Laboratories Inc
Publication of EP0079959A1 publication Critical patent/EP0079959A1/fr
Publication of EP0079959A4 publication Critical patent/EP0079959A4/fr
Application granted granted Critical
Publication of EP0079959B1 publication Critical patent/EP0079959B1/fr
Expired legal-status Critical Current

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G19/00—Processes using magnetic patterns; Apparatus therefor, i.e. magnetography
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/385—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective supply of electric current or selective application of magnetism to a printing or impression-transfer material
    • B41J2/43—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective supply of electric current or selective application of magnetism to a printing or impression-transfer material for magnetic printing
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/17—Construction or disposition of windings
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/187—Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium; Pole pieces; Gap features

Definitions

  • This invention relates to a magnetic recording head for recording on a magnetizable medium responsive to a signal current applied to said head according to the preamble of the claim.
  • a recording head is known from US-A 2532100.
  • the first deals with the generation of possibly destructive heat at and near the recording zone when recording at high speeds. As such, a reduction in the electrical resistance of the individual recording elements would be appropriate.
  • a third concern involves the need for large and relatively expensive driving components providing the high recording current.
  • the large driving components create packaging and other problems, especially for wider recording head design.
  • US-4 025 927 requires the creation of a physical virtually square notch in each of the recording elements.
  • the height of this notch must be relatively large as compared with the width of the recording elements, in the vicinity of the recording zone (e.g. in a recording head with 250 recording elements per inch, the height of the notch typically would be approximately 1.5x10- 3 in. and the width of recording element is 2x10- 3 in., with a typical recording zone length being on the order of 3,5x10- 3 in.).
  • creation of this notch within such specifications can become quite difficult in terms of mass production and, thereof, is of concern.
  • the present invention allows a substantial reduction in the recording current utilized in the conductor the need is obviated for a geometric shift of the current flow path at the record zone toward the recording medium to articulately define the recording zone of each recording element.
  • the present invention achieves a highly articulate shift in the magnetic field around the current-carrying conductor, in localizing the recording function thereof without for example the notch construction depicted in US-4 025 927.
  • a further advantage of the present invention is that with thin film metalization construction techniques, one can with great accuracy selectively place regions of magnetic thin film behind the conductors, i.e. the major surface of the current-carrying recording element facing away from the recording medium (which is the surface normally attached to or otherwise contiguous with a support material or substrate usually in the form of a mandrel).
  • Fig. 1A depicts the Nelson Patent (US-A-4025927) magnetic recording scheme for magnetography.
  • a single illustrated recording element 100 is positioned above a magnetic recording medium 101 that is moving with a velocity of v in the direction indicated.
  • an electric current pulse I flows through the recording element 100 generating a magnetic field around the recording element as indicated by relative field lines H, and H 2 .
  • the recording element is geometrically thinned down for a predetermined length Z to define the recording zone. This reduction of the recording element at the recording zone causes a stronger magnetic field H 2 , as compared with H i , to be experienced by the recording medium.
  • Fig. 1 B The interaction of H 1 and H 2 of Fig. 1A with a properly selected magnetic medium is illustrated in Fig. 1 B.
  • the magnetic medium has a rather "square" B-H characteristic and has been premagnetized.
  • a magnitude for I such that and due to the geometrical configuration of the recording element 100 where, He is the magnetic coercive force corresponding with one of the intrinsic properties of the recording magnetic medium.
  • Figs. 1A and 1 B lends itself to the design and fabrication of recording heads, with many recording elements of very fine structure, and utilizing "etch foil" fabrication technology. However, it requires relatively high recording current I to effect magnetic recording.
  • Fig. 2A illustrates an improved recording head in terms of a substantially reduced recording current.
  • the improvement is achieved through the introduction of a body of material 102 with magnetic permeability p substantially higher than ⁇ o (the permeability of air) into the recording zone.
  • a single block of material 102 extends from recording element to recording element at the respective recording zones, with the latter forming a straight row. It is to be noted however, that individual portions of material 102 may be provided to each or selected ones of the recording elements.
  • Fig. 2A the recording element 1 00b is excited by the recording current I.
  • the resultant magnetic field intensity H is now subjected to a path comprising the path I within the high permeability material 102, the path length ⁇ l in air and l m corresponding with the path length in the magnetic medium 101 itself. Knowing the relation between the induced magnetic field B and field intensity H as given by and carrying the line integral of formula (4) over the total path shown in Fig. 2A for element 100b, results in (approximated for the case of B entering the magnetic medium perpendicularly).
  • equation (5) becomes because I is also in air.
  • Fig. 2B there is illustrated in cross-section the relationship between one of the conductive recording elements of Fig. 2A (e.g. element 100b), the magnetic medium 101 and the material 102.
  • the material contacts the recording element at the surface thereof which is distal to the recording medium, whereas in the other illustrated case, the material surrounds the conductor except for the surface thereof which is proximate to the recording medium.
  • the length All represents the separation gap between material 102 and the medium 101 for the case of the material having a thickness represented by 106, and A1 2 represents the gap for a material 102 having a greater thickness, as indicated by 107 (i.e. material 102 in this case extending around the conductor except at the side facing the medium 101).
  • All and A1 2 thus respectively represent that length of the illustrated field lirie around the conductor 100b in air between the medium 101 and the material 102. As before, represents the length of the field line inside the material 102 and l m represents the length of the field line inside the magnetic medium 101.
  • Curve 103 represents achievable reduction of current for a record head with material 102 deposited behind the recording elements to the depth of level 106 (Fig. 2B).
  • Curve 104 corresponds with achievable reduction of current for a recording head with the same material 102 deposited behind and in between the recording elements to the level 107.
  • the layer 102 may be a magnetic pigmented epoxy having a permeability in the range of 5 to 5.5.
  • curve 103 asymptotically approaches the normalized value of 0.5, which suggests up to a 50% reduction in the recording current; moreover, curve 104 approaches the level of 0.3 for large ⁇ / ⁇ o , indicating possible current reductions up to 70%.
  • utilization of a high permeability material having thickness level 107 and permeability of say 5.5 would be able to yield a current reduction on the order of 4.8 amps or a resultant recording current of 8.2 amps.
  • Figs. 3-6 Further improvements are illustrated in Figs. 3-6.
  • the recording head arrangements depicted therein require no geometrical change of the recording zone, i.e. no physical change of the plane of current flow relative to the magnetic medium.
  • This allows the design and construction of "flat" record heads utilizing, as example, “etch foil” technology or “metallization” techniques or a combination of these fabrication technologies.
  • Fig. 3 depicts a single recording element 100 of a recording head positioned on a magnetic medium 101.
  • a high permeability material 108 is deposited behind the recording element 100 in the record zone which shunts the magnetic field represented by field lines 109 in material 108, which enables a substantially higher recording magnetic field as compared with 8 0 , represented in Fig. 3 by field line 110.
  • the recording zone is in this way at least partially defined, and without the need for a geometrical change.
  • material 108 can (as shown by the breakaway) be a continuous piece transcending across the entire recording head at the respective record zones of the recording elements. See in this regard Fig. 7 in particular.
  • Fig. 5 illustrates a preferred embodiment having the combined features of the record head arrangements shown in Figs. 3 and 4.
  • the recording zone is defined by the discontinuity in material 111 and the presence of a second section of high permeability material 108, located on the back of the recording element to effect a reduction in the recording current due to its magnetic shunting characteristic.
  • the interaction of 8, with the magnetic medium is minimized by the shielding effect of material 111.
  • Fig. 5 represents an especially advantageous recording scheme having "flat" geometry, reduced recording current requirements, and reduced (shielded) magnetic field outside of the recording zone.
  • Fig. 6 shows that the shunting high permeability material 108 of Fig. 5 can extend beyond the recording zone in either direction.
  • the extension of 108 to relatively large distances could tend to increase the inductance, L, of the recording elements which in turn would tend to increase the circuit time constant UR that would lead to reduced recording speed.
  • Fig. 8 depicts a portion of a record head with the material 108 deposited on the substrate 112. In this configuration the recording zone 114 will be closest to the magnetic medium. It should be noted that deposition of high permeability material 108 in between the recording elements in Fig. 7 and Fig. 8 would lead to further reduction in the recording current, in similar manner as illustrated in Fig. 2B.
  • the field can be shunted (e.g. Fig. 4) by for example the thin magnetic material layer 111 (soft iron, possibly iron-nickel, etc.) in a shielding action to avoid the field around the conductor from being strong enough to record on the tape medium.
  • the conductor and its associated field is thus seen as it exists with and without the thin magnetic film overlay.
  • the recording field ⁇ H' associated with the magnetic biasing is smaller than AH, thus suggesting that the recording current under such a magnetic biasing condition can be smaller since AH is proportional to the recording current.
  • a 20% reduction in the recording current can be achieved by imposing a biasing magnetic field of about 200 gauss.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Heads (AREA)
  • Recording Or Reproducing By Magnetic Means (AREA)

Claims (2)

1. Tête d'enregistrement magnétographique destiné à enregistrer sur un support (101) aimantable, en réponse à un courant de signal admis à ladite tête, et comprenant un conducteur (100a, 100b, 100c) dans lequel ledit courant de signal est conduit et produit un champ magnétique qui, au droit d'une section dudit conducteur se trouvant le plus proche dudit support (101) et étant défini comme une zone d'enregistrement, traverse ledit support aimantable et effectue un enregistrement sur celui-ci, et une dérivation magnétique (102), en un matériau hautement perméable et disposée à ladite zone d'enregistrement, sur un côté dudit conducteur (100a, 100b, 100c) qui est opposé à un autre côté de celui-ci, le plus proche dudit support (101), ladite dérivation (102) permettant de créer autour dudit conducteur, dans la zone d'enregistrement, des lignes de flux en un nombre plus grand que dans une région entourant ledit conducteur et éloignée de ladite zone d'enregistrement, ladite dérivation déplaçant également le champ magnétique qui entoure ledit conducteur, de manière qu'elle l'approche davantage dudit support (101) dans la zone dlenregistrement, caractérisée en ce que ladite dérivation magnétique (102) est aussi dotée de rémanence magnétique et est aimantée avant qu'il ne s'effectue un enregistrement sur ledit support (101), et produit en champ magnétique qui traverse ledit support (101) et fournit une préaimantation dans la même direction que le champ magnétique généré par le courant de signal, la préaimantation seule n'effectuant pas d'enregistrement sur ledit support (101), mais provoquant un enregistrement sur ledit support (101) dès qu'elle est ajoutée au champ magnétique établi par ledit courant de'signal.
2. L'invention selon la revendication 1, caractérisée en ce que ledit conducteur (100a, 100b, 100c) est généralement plat, et ladite dérivation magnétique (102) recouvre ledit conducteur (100a, 100b, 100c)'à l'exception de cet autre côté de celui-ci qui est le plus proche dudit support (101).
EP82902146A 1981-06-01 1982-05-28 Tete d'enregistrement magnetographique Expired EP0079959B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US06/268,934 US4405960A (en) 1981-06-01 1981-06-01 Magnetographic recording heads
US268934 1981-06-01

Publications (3)

Publication Number Publication Date
EP0079959A1 EP0079959A1 (fr) 1983-06-01
EP0079959A4 EP0079959A4 (fr) 1983-09-26
EP0079959B1 true EP0079959B1 (fr) 1986-04-23

Family

ID=23025137

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82902146A Expired EP0079959B1 (fr) 1981-06-01 1982-05-28 Tete d'enregistrement magnetographique

Country Status (6)

Country Link
US (1) US4405960A (fr)
EP (1) EP0079959B1 (fr)
JP (1) JPS58500987A (fr)
DE (1) DE3270734D1 (fr)
IT (1) IT1198372B (fr)
WO (1) WO1982004342A1 (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4745509A (en) * 1981-08-21 1988-05-17 Matsushita Electric Industrial Company, Limited Magnetic head with improved supporter for perpendicular magnetization recording
US4517616A (en) * 1982-04-12 1985-05-14 Memorex Corporation Thin film magnetic recording transducer having embedded pole piece design
JPH0731362Y2 (ja) * 1988-06-03 1995-07-19 アルプス電気株式会社 薄膜磁気ヘッドおよび浮動式磁気ヘッド
US6917493B2 (en) * 2001-08-28 2005-07-12 Seagate Technology Llc Ampere head with perpendicular magnetic field
US6665136B2 (en) 2001-08-28 2003-12-16 Seagate Technology Llc Recording heads using magnetic fields generated locally from high current densities in a thin film wire
US7212367B2 (en) * 2004-06-16 2007-05-01 Seagate Technology Llc Ampere wire write head with confined magnetic fields
US20080068750A1 (en) * 2006-09-19 2008-03-20 International Business Machines Corporation Planar Write Module And Hybrid Planar Write-Vertical Read Bidirectional Tape Head
US20080068752A1 (en) * 2006-09-19 2008-03-20 International Business Machines Corporation Planar Bidirectional Tape Head With Planar Read And Write Elements
US7978429B2 (en) * 2006-09-19 2011-07-12 International Business Machines Corporation Low track pitch write module and bidirectional tape head

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2532100A (en) * 1947-05-29 1950-11-28 Indiana Steel Products Co Electromagnetic transducer head
GB991637A (en) * 1962-05-12 1965-05-12 Ferranti Ltd Improvements relating to electromagnetic transducers
US3475739A (en) * 1965-10-01 1969-10-28 Litton Business Systems Inc Mounting for an air bearing magnetic transducer head
US3626396A (en) * 1968-10-03 1971-12-07 Ibm Thin-film magnetic recording head
JPS5038325B1 (fr) * 1970-12-25 1975-12-09
US4025927A (en) * 1975-07-10 1977-05-24 Cubic Photo Products Division Multilayer magnetic image recording head
SU705509A1 (ru) * 1978-06-05 1979-12-25 Предприятие П/Я А-3759 Магнитна головка
DE3070076D1 (en) * 1979-11-05 1985-03-14 Genicom Corp Magnetic printing head having a high signal-to-noise ratio

Also Published As

Publication number Publication date
IT1198372B (it) 1988-12-21
DE3270734D1 (en) 1986-05-28
US4405960A (en) 1983-09-20
JPS58500987A (ja) 1983-06-23
IT8221622A0 (it) 1982-06-01
WO1982004342A1 (fr) 1982-12-09
EP0079959A1 (fr) 1983-06-01
EP0079959A4 (fr) 1983-09-26

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